Exothermic

Exothermic process: a change that releases heat.This pneumonic will help you remember what Exothermic means:EXothermic = EXitThis means that the heat exits the reaction and warms up the surroundings which we feel.

This shows the heat leaving the reaction. We feel the surroundings get warmer. We can NEVER feel the reaction's temperature because the energy goes into the bonds of the molecules. We can't touch the bonds of molecules!

Endothermic

Endothermic process: a change that requires (or absorbs) heat.

This pneumonic will help you remember what Endothermic means:ENdothermic = ENterThis means that the heat enters the reaction or steals it away so that we don't feel it.

This shows the heat entering the reaction. We feel the surroundings get cold. We NEVER feel the temperature of the reaction because the heat goes into the bonds of the molecules. We can't touch a bond!

Activation Energy

Activation energy is the energy required to start a reaction. Reactions don't start all by themselves. They need a nudge. So you have to add some energy. It can be in the form of fire, like a match. Or it could be a liquid that has more energy than a solid.